Automatic grinding and machining apparatus

ABSTRACT

Apparatus suitable for automatically positioning a stator and grinding a resinous coating from a cylindrical surface of a motor stator or for machining any surface of a member having a portion alignable with the machining or grinding means. The apparatus includes a rotatable horizontal shaft mounted on an upright frame, the frame being movable to and from a stator or member support table, the table being controllably movable vertically, laterally and angularly of the shaft in order to align the axis of a stator or a portion of a member on the table with the shaft, the shaft having a laterally-extending arm on the end nearer the table, a spindle adjustable movable on the arm to any radial position with respect to the shaft, a sensor detachably mounted on the spindle for measuring any non-alignment in any of the vertical, horizontal and angular directions of the stator axis or other member with respect to that of the shaft, operatively associated means between the sensor and the table for adjusting the support table so that the stator axis is brought into coaxial alignment with the shaft, and abrasion or machining means detachably mounted on the spindle and operable, for example, for grinding off a resinous coating on the stator surface as the laterally extending arm is rotated on the shaft and arm moves the abrasion means around and in contact with the stator surface.

United States Patent 1191 Kipple et al. Nov. 6, 1973 1 1 AUTOMATICGRINDING AND MACHINING APPARATUS 57 ABSTRACT [75] Inventors: Harry P.Kipple, Pittsburgh, Pa.;

Francis C. Kapperman, deceased, late of Eggertsville, N.Y. by Dorothy M.Kapperman, administratrix; Virgil J. Cozzarin, Clarence, NY.

[73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

[22] Filed: Aug. 9, 1971 [21] Appl. No.: 170,006

52 US. Cl. 51 43, 51/165.75

[51] Int. Cl 1324b 5/06 [58] Field of Search 51/43, 165.75;

[56] References Cited UNITEDSTATES PATENTS 2,458,765 l/l949 Bryant 51/432,505,812 5/1950 Theimer..... 51/l65.75

2,458,472 l/l949 irwin.. 5l/43 X 2,340,210 l/l944 Armitage 90/15 R2,639,562 5/1953. Balsiger 5l/l65.75

2,521,210 9/1950 Fulmer 5l/43 X Primary Examiner -Harold D. WhiteheadAttorney-F. Shapoe Apparatus suitable for automatically positioning astator and grinding a resinous coating from a cylindrical surface of amotor stator or for machining any surface of a member having a portionalignable with the machining or grinding means. The apparatus includes arotatable horizontal shaft mounted on an upright frame, the frame beingmovable to and from a stator or member support table, the table beingcontrollably movable vertically, laterally and angularly of the shaft inorder to align the axis of a stator or a portion of a member on thetable with the shaft, the shaft having a laterally-extending arm on theend nearer the table, a spindle adjustable movable on the arm to anyradial position with respect to the shaft, a sensor detachably mountedon the spindle for measuring any nonalignment in any of the vertical,horizontal and angular directions of the stator axis or other memberwith respect to that of the shaft, operatively associated means betweenthe sensor and the table for adjusting the support table so that thestator axis is brought into coaxial alignment with the shaft, andabrasion or machining means detachably mounted on the spindle andoperable, for example, for grinding off a resinous coating on the statorsurface as the laterally extending arm is rotated on the shaft and armmoves the abrasion means around and in contact with the stator surface.

17 Claims, 7 Drawing Figures PAIENIEDnuv 8 ms SHEET 1 Of 5 FIG. I.

PATENTED NOV 6 I973 SHEET 2 UP 5 SHEET 5 BF 5 3 V swirl/lawman FIG. 7.

CROSS REFERENCE TO RELATED APPLICATION This invention is related toapplication Ser. No. 143,034, filed May 13, 1971.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to apparatus for automatically aligning a motor stator or othermember in a desired position with respect to an abrasion or machiningmeans and then grinding away a coating of cured resin from the statorsurface or effecting a machining operation on the member.

2. Description of the Prior Art Rotating electrical apparatus such asmotors and generators, employ insulated coils comprising central coreslot portions and end turn portions. The preparation of coils, windings,or conductors for insertion into slots of magnetizable cores by priormethods have involved the time consuming and costly process of applyinginsulation tape, wrappers, and slot cell liners to the coil portions,such as disclosed in U.S. Pat. No. 3,054,880. The process wasparticularly involved, time consuming and costly where it was employedin the. repair of coils for motors and generators.

A method that would eliminate or reduce the amount of taping andwrapping required for producing all types of rewound rotating apparatuswould be desirable. In addition to reducing the labor required in therewinding of the electrical apparatus, a reduction of subsequenttreatment cycles has been sought. More particularly, in the area ofform-wound coils for stators, rotors, and armatures, with, for example,direct current fields and rotating fields, the methods remain the same;i.e., mostly hand-tapingof assembled conductors, varnish treatment, andapproximately 12 hour baking cycles.

The foregoing problems are of greater moment where repair shops for suchapparatus are involved. Repair shops handle apparatus of various sizesand are therefore necessarily faced with the necessity of preparing andapplying a wide variety of non-standardized coil shapes and sizes andusing different varnishes requiring different modes of application andcuring procedures. For example, repair shops must be prepared to handlecomponents of rotating apparatus varying in diameter from about 6 inchesup to 6 feet or more, and manufactured at a time going back as much as50 years or more. In such circumstances, the repair methods employedmust be flexibly and readily adapted to a maximum output at a minimumcost.

More particularly, where it is expedient to spray powdered resin ontocoils of a motor or similar electrical devices automatically, such asshown in application Ser. No. 143,034, filed May 13, 1971, the powderedresin is applied not only to the coils but also onto adjacent areasincluding the bore surfaces of a motor stator in order to facilitate thedeposition of a predetermined thickness of a resinous coating onselected areas of a coil and into the coil slots in the core.Thereafter, any spillage or application of resin upon undesired areassuch as the bore surface of the core of the stator must be removed sincethe stator must allow the rotor to op-' erate closely to its surfacewithout contact therebetween. If removal of the resin from the undesiredareas were dependent upon manual methods it would not be Z expedient oreconomical to apply the resinous coating to the coils.

While the apparatus has been especially designed to enable excess resinto be ground off of a stator bore, the apparatus lends itself togrinding or machining any alignable portion of a stator or other member.The alignment in any of the horizontal, vertical and axial directions ofthe stator or other member to the grinding or abrasion means or amachining tool such as a milling cutter, can be automatically andreadily carried out. While the description hereinafter will be directedto the removal of excess resin from the bore surfaces of a stator, itwill be understood that any machining of a surface of a member may besimilarly effected.

SUMMARY OF THE INVENTION It has been found in accordance with thisinvention that the foregoing problems may be overcome by employment ofan apparatus for automatically precisely grinding the resinous coatingfrom the metal core surfaces of the bore of a motor stator.

Broadly, the invention comprises apparatus for working with a tool someportion of a member such as a stator which portion requires alignmentwith the'tool, the apparatus comprising a base on which is mounted aframe for linear reciprocating movement to and from a support table,also on the base, on which is mounted the member to be worked, and meansfor moving the support table vertically, laterally in a horizontalplane, and angularly about a vertical axis so as to enable the member tobe moved therewith so as to align said portion with the axis of arotatable tool support means carried by the frame. The rotatable toolsupport means comprises an arm movable along a radius with respect tosaid axis, and means bn the arm for supporting the tool and a sensingmeans. The sensing means can deter mine any misalignment of the saidportion of the member and is operatively associated with the means formoving the support table so as to move the support and the memberthereon to precisely align the portion of the member with the axis ofrotation. The arm includes an adjusted lever mechanism for moving thetool and sensing means a small distance for fine positioning.

More specifically, the apparatus includes a rotatable horizontal shaftsuitably mounted'on an upright frame, a stat'or support table'havingmeans for controllably moving the table vertically, laterally, ad abouta vertical axis with respect to the axis of the shaft in order to alignthe axis of the bore of the stator with the shaft, means forreciprocating the frame and table toward or away from each other, theshaft having a laterally extendingarm on the end nearer the table, aspindle on the arm and being adjustably rotatably movable thereon to anyposition about the shaft, sensor means detachablymounted on the spindlefor measuring any eccentricity of alignment of the stator axis withrespect to that of the shaft, means between the sensor and the table foradjusting the-stator axis into coaxial alignment with the shaft, andabrasion means detachably mounted on the spindle for grinding away aresinous coating as the rotating arm moves the abrasive means around thestator surface.

The advantage of the apparatus is that it is automatically operative toalign the stator precisely with respect to the shaft axis and operableto remove excess cured resin from the surface of the bore of a statorand which apparatus is adapted for use with stators of difframe.

ferent sizes, such as are being processed in a motor repair shop withprecision and at a high output and with a low cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view, partlyin section, of the apparatus of the present invention;

FIG. 2 is a plan view on a smaller scale than FIG. 1 of the apparatus;

FIG. 3 is an end view of the table portion of the apparatus without amotor stator thereon taken on the line IlI-III of FIG. 1;

FIG. 4 is an enlarged plan view of the lift table with the centerportion of the platform broken away, taken on the line IV-IV of FIG. 5;

FIG. 5 is a vertical sectional view, taken on the line V-V of FIG. 4,and showing a motor stator mounted on the platform;

FIG. 6 is a fragmentary elevational view 'of the mounting means for thespindle comprising a grinder motor and showing the manner in which asensing device may be mounted-to facilitate the proper alignment of themotor stator (shown in section) with respect to the spindle and FIG. 7is a fragmentary view similar to FIG. 6, showing a grinder in operativeposition.

DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus of the presentinvention is generally indicated at 10 in FIG. 1, and it includes a base12, a grinder support frame 14, and a lift table 16 for supporting amotor stator 18.

The base 12 includes an upper support plate 20 disposed at a distanceabove a floor plate 22 in order to provide clearance for a plurality ofjack screws which are used for raising and lowering the lift table 16.The upper support plate 20 carries a pair of spaced tracks 26 (FIG. 2)on which the support frame 14 is mounted for reciprocating movement toand from table 16. As shown in FIG. 2 the tracks 26 extendlongitudinally on the support plate 20 and in the direction of the lifttable 16, whereby the frame 14 is movable toward the lift table up'to aposition indicated by broken lines 28. Though the frame 14 is disclosedasbein'g movable'toward and away from the table, it is understood thatalternatively the table may be movable to and from the More particularlythe support frame 14 is a mounting means for a circular grinding wheel30 which during use is positioned by the frame into the stator 18 suchas indicated by broken line positions 30a and 30b in FIG. 1 and FIG. 7,for grinding away a layer 32 of cured resin which has been applied ontothe bore surface 34 of the stator when it was applied as insulation forthe coils and windings 33 of the stator. For such longitudinalreciprocating movement, the support frame 14 includes a support 36 whichslidably engages the tracks 26, a pair of spaced upright support members38 and 40 and a horizontal plate 42 attached to and extending betweenthe members 38 and 40. The frame 14 also includes side housing plates 44and 46 as well as a top plate 48.

As shown in FIG. 1 a shaft50 is rotatably mounted in suitable bearings52 and 54 on and between the support members 38 and 40. A sprocket 56 ismounted on the shaft 50 and is driven by a continuous link chain 58which extends over and between said sprocket and a sprocket 60 at theoutput end of a speed reducer 62 which is driven by a motor 64. Thespeed reducer and the motor being mounted on the plate 42.

The right end of the shaft 50 projects beyond support and carries meansfor supporting and rotating the grinding wheel 30 in desired circularpositions such as within the stator 18. Such means includes an armgenerally indicated at 66 which is fixedly attached to the ends of theshaft 50, whereby the grinding wheel 30 may be rotated in any circularpath of travel from the axis of shaft 50 to the circle 68 as indicatedin FIG. 3. As shown in FIG. 1 a shorter portion of the arm is disposedon the upper side of the axis of the shaft 50 while a longer portioncarrying grinder 30 is disposed on the lower side thereof so that as thearm rotates the extremity of the shorter portion at 86 describes a fixedcircular path of travel 70 (FIG. 3). As shown in FIGS. 1 and 3 the arm66 includes a pair of elongated support members 72 and 74 the upper andlower ends of which are secured together by similar end plates 76 and78, respectively. The support members 72 and 74 are attached to amounting plate 80 which in turn is fixedly secured to the right end ofthe shaft 50 as viewed in FIG. 1. I I

A screw threaded shaft 82 is disposed between and rotatably mounted inthe end plates 76.and 78 and is provided with drive means at the upperend which means includes a reversible motor 84, a sprocket 86 fixed tothe upper end of the screw threaded shaft 82 and a drive chain 88 (FIG.3) engaging sprocket 86 and driven by the motor. Accordingly, the screw82 may be rotated either clockwise or counterclockwise by operation ofmotor 84.

The means by which the grinding wheel 30 is attached to the arm 66includes a slide or mounting block 90 and a bell crank linkage assemblygenerally indicated at 92 for mounting of the grinding wheel 30 on theouter end of a spindle 94 of a motor 96 which may be an air driven or anelectrical motor.-The slide 90 has bearing surfaces slidably contactingthe support members 72 and 74. The slide 90 has a bore 98 throughtively,,of the bore 98. In addition, a threaded nut 104 rigidly fixed toslide engages the screw 82 so that rotation of the screw by motor 84causes the slide 90 to move along its length. 7

Th slide 90 has affixed an outwardly extending arm 106 carrying thelinkage assembly 92. The'linkage as sembly 92 comprises a pair of bellcrank levers l 10 and 112 mounted on pivot pins 1 l4 and 115 with anupper link 108 connecting the upper ends of the bell cranks 110 and 112.Pivot pins 114 and 115 are on a line parallel to the axis of shaft 50. Apair of clamps 116 and l 18 are attached by pivot pins 120 and 121 tothe other ends of the levers 110 and 112, respectively, for holding themotor 96 in place. The arrangement of the bell crank levers, link 108,and pivot pins 114, 115, 130, and 311 is such that the spindle 94 is onan axis substantially parallel to thatof the shaft 50.

The link assembly 92 is actuated for movement by an inflatable bellowsmember 122, which may comprise a rubber bladder or a corrugated metalcylinder, which is disposed between a pair of mounting plates 124 and126, the former of whichis secured to one side of the slide 90 and theother of which is mounted on a mounting member 128 to which thelink 108andthe lever 110 are pivotally attached by a pin 130. In the deflatedposition of the bellows 122 the motor 96 and the grinding wheel 30 areinretracted position as shown in FIG'. 1. However, when the bellows 122 isinflated link 108 and the bell crank levers move clockwise and the pivotpins 120 and 121 drop down so that the motor 96 and the grinding wheel30 are moved radially downwardly outwardly to a position shown by thebroken line 132, thereby facilitating insertion and adjustment of thegrinding wheel 30 within the stator 18 to control the depth of grindingof the stator. The link assembly 92 is actuated to provide parallellinkage motion to the motor 96 and the grinding wheel 30 upon movementof the link 108 in the direction of the arrow 134 in response toinflation of the bellows 122.

As shown in FIG. 1 an air pressure conduit 136, extending through theslide 90, communicates with the interior of the bellows 122, and byintermediate flexible conduit means (not shown) is connected to anoutlet 138 which communicates in turn with a conduit 140 extendingthrough the shaft 50 to the left extremity thereof where it connectswith an air tight slip coupling 141 connected to conduit 142 whichextends to a source of compressed air or gas such as at pressure fromabout I to pounds per square inch. A helical compression spring 144which is disposed between the upturn portion of the lever 110 and aportion 146 of the arm 106 tends to pull the link assembly 92 back tothe original position when the bellows 122 is deflated with the link 108moving in the opposite direction to the arrow 134, whereby the motor 96and the grinding wheel 30 are returned to the solid line positions asshown in FIG. 1. The purpose of the air inflatable bellows 122 is toapply a yielding or resilient pressure to the grinding wheel 30 so thatthere is sufficient force to enable the layer 32 of cured resin to beground off from the surface 34 of the stator. However, when the resinlayer 32 is removed and the harder metal surface 34 is exposed itresists the abrasive action of the grinding wheel 30 at such lightpressure and a minimal amount of metal is abraded. A maximum pressureof, for exampie, 7 psi in the relatively small area bellows 122 issufficient to enable the wheel 30 to be effective in removing the softercured resin layer but less effective to remove the metal surface.-However, in machining metal, higher pressures may be applied to a largerbellows so that a grinding wheel or milling cutter may be moreeffective.

The support frame 14 is movable over the tracks 26, to which it issecured in a conventional manner such as by interlocking dogs or rollerportions fitting under a head or the tracks, by means which includethreaded screw 148, the left end of which is secured rigidly to'anupright member 150 extending from the support plate 20. An axiallyrestrained rotatable threaded nut (not shown) within a housing 152,engages the screw which nut is driven by a reversible motor 154 mountedon the frame and a drive belt 156 which rotates a worm gear whichengages a geared periphery on the nut. Energization of motor 154 causesthe nut to turn and by its threaded engagement with screw 148 causes theframe 14 to move to the left or to the right as seen in Fig. 1.

The lift table 16 has the function of placingthe center axis of thestator in vertical alignment with the axis of the shaft 50 so that theaxis of the cylindrical bore surface 34 of the stator is concentric withthe path of travel 68 (FIG. 3) of the grinding wheel 30 during operationthereof. The lift table is provided with means for moving the table inthree different directions; namely, vertically, transversely in ahorizontal plane, and for making angular or skew adjustments to the axisof the shaft 50. The grinding wheel 30, being mounted for movement inline with the tracks 28, moves only horizontally toward and away fromthe lift table and more particularly the motor stator 18. Referring toFIG. 6 the means for precisely aligning the axis 158 of the stator 18with the axis of the shaft 50 includes a proximity switch or sensor 160mounted on spindle 94 and associated with it are means operativelyassociated with the lift table 16 for moving the table vertically,horizontally and in skew adjustment. The sensor 160 may comprise amagnetic switch that detects all eIectro-conductive metals which enterits magnetic field. A suitable sensor for this purpose is one of a lineof proximity switches for detecting ferromagnetic metal such as made andsold by Micro-Swtich, a Division of Honeywell, Corp. of Freeport, Ill.When a stator 18 is placed on the table its axis 158 is located by thevisual observations of the operator as proximate to the axis of theshaft 50 as possible. Thereafter the support frame 14 is moved towardsthe stator and the sensor 160 is placed in position substantially asshown in FIG. 6. Although the sensor 160 is shown as a separateattachment on the spindle 94 of the motor 96, the sensor may be a partof the assembly of the housing in which spindle 94 rotates, and thesensor may be movable into and out of operative position on a pivot onthe housing. During use of the sensor 160, the motor 96 is notoperating; rather the shaft 50 is turned to enable a magnetic fluxtransmitted by the sensor to sense the proximity (say, within )4 inch)of the surface 34 of the'ferromagentic portion of the stator 18 and avoltage is produced proportional to the distance of the sensor to theferromagnetic material. As the arm 66 (FIG. 1) is rotated the senor 160is slowly rotated in a circle around the axis of the shaft 50 and anymisalignment of the stator with respect thereto is detected by thesensor and a variable voltage is transmitted to a receiver 162 (FIG. 2)which also has a signal as to the position of arm 66 o'n shaft 50 andthus senses the voltage variation and its position and which in turntransmits an electrical output to one of the mechanisms associated withthe table 16 to correct the out of alignment by elevating, movinghorizontally or turning table 16. I

When the sensor 160 moves from the lower position as shown in FIG. 6 tothe upper position 160a, any voltage variation generated causes receiver162 to actuate the means for lifting or lowering the table to a desiredposition of less voltage variation (i.e., move the stator away fromthatpoint at which the sensor is closest to the stator bore surfaces). Onthe other hand when the sensor l60 is in horizontal position such asposition 160b on the right or left side of the stator 18, means formoving the table transversely on a horizontal plane with respect to theaxis 158 are actuated by the receiver porportional to the voltagevariation; so that the stator bore is not as closev to the sensor as itsprevious position. Finally, when the sensor 160 is advanced from thefront to the back of the stator, that. is, to the right within thestator to a position 160c (FIG. 6), any misalignment of the right-handend of the axis 158 as compared with the axis of the shaft 50 iscorrected by the receiver 162 energizing the means associated with the.7 table l6'for making skew or angle adjustments. of the stator byrotating the table 16 about a vertical axis.

Several procedures may be followed in employing the sensor 160 to alignthe stator in full axial parallelism with shaft 50. The arm 92 withsensor 160 may be rotated at the front end of the stator bore 34 and thetable 16 moved until the front end of the stator is centered about shaft50. The arm 92 may then be stopped from rotating and the sensor 160 leftin a position halfway up, namely at the midline of one side or the otherof the stator, and the frame 14 caused to move the sensor 160 toward theback of the bore 34. If in the front to back movement of the sensor 160,the bore wall either approaches or recedes from the sensor, the voltageoutput of the sensor will vary correspondingly and the receiver 162 willput out asignal to rotate the table 16 until the path of the sensor isat a constant distance from the adjacent bore wall. The sensor 160 isthen caused to revolve; for example about the mid point of the bore, andany horizontal misalignment will be sensed by the sensor 160, thereceiver 162 caused to send appropriate control signals to thehorizontal actuators of the table LIFT TABLE As shown in FIGS. 4 and 5the lift table 16 includes a table 168, a base plate 170, and a platform172 pivotally mounted on the base plate 170, all supported on plate 20.The table 168 supports a pair of spaced electromagnets 174 and 176(FIGS. 1, 2 and 5) on which the stator 18 is mounted and held in placewhen the electromagnets are energized. Obviously, clamps or nut and boltassemblies may be utilized to hold stator 18 on platform 172. The table168 is supported by four screw jacks 24, one near each corner of thetable as well as 1650 as to move it, the axis 158 of the stator 18, intoaxial alignment with the shaft 50. If necessary for the most precisealignment, these relative sensor movements may be repeated to make fivecorrections.

Alternatively, the, sensor is initially moved back and forth at aboutthe mid-point of the bore and the table 16 rotated to get the bore axisparallel to shaft 50. Thereafter the sensor is revolved at the front orback ends of the bore so as to enable the table 16 to be moved up ordown, and sideways to secure exact alignment of the axis of the statorwith the shaft 50. Adjustments can be made for transverse settings aswell as skew adjustments of table 16 by a combination of automatic andmanual operations of the proximity sensor 160, until the axis 158 of thestator is brought into substantial alignment within a 0.01 of an inch orso with the axis of the shaft 50. Thereafter the aligned stator is readyfor grinding away the layer 32 of resin from the innercylindricalsurface 34 of the stator.

The grinding wheel is composed of a suitable abrasive, in the form of asolid abrasive grinding wheel or an abrasive belt, or even a stiff wirebrush. The particles of abrasive materal in the wheel or belt may becomposed of a suitable material such as silicon carbide or alumina. Thegrinding wheel 30 moves both by rotation of shaft 50 and arm 92 so thatit contacts the interior of the stator as. shown in FIG. 5 and by beingrotated by themotor 96 whereby the abrasive contacts the resin layer 32by appropriate air pressure, in the inflated bellows 122.- As resin isground off, the bellows 122 automatically moves the grinding wheel 30radially outwardly on the arm 66 in order to contact additional resin inthe layer 32 close to the surface 34 of the stator. When the layer 32 isremoved, the grinding wheel 30 is moved, either by manual control orautomatically from position 300 ultimately to position 30b as shown inFIG. 7 by actuating the motor 154 (FIG. 1) to drive the frame to theright as viewed in FIG. 7. As evident from FIG. 2 limit switches 164 and166 are set to control the movement of frame 14 on tracks 26 tocorrespond to the width of the stator, and the horizontal movement ofthe frame 14 is stopped at the set limits by the switches turning offmotor 154. v

a pair of guide rods 178 and 180, one of which is disposed between onepair of screw jacks and the other of which is disposed between the otherpair of screw jacks. The platform 172 below the table 168 is slidablymounted on the plate 170 and friction between the platform and the plateis minimized by the provision of bearing strips 182 which are attachedto the undersurface of the platform at the four peripheral edgesthereof. The bearing strips 182 are preferably composed of materialhaving low friction properties such as nylon or polytetrofluoroethyleneresin.

The lower end of the screw jacks 24 and the guide rods 178 extendthrough relatively large corresponding apertures in the platform 172 aswell as through aligned apertures 184 and 186 in the plates 170 and 20,respectively. The plate 170 is fixedly secured to'the support plate 20by several spaced nut and bolt assemblies 188.

Each screw jack 24 is coupled with a nut assembly 190 through which thescrew jack extends to the undersurface 168 where it is rigidly secured.Each nut assembly 190 includes a sprocket 192 which is actuated bysimilar link chains 194 each of which is driven by spaced sprockets 196on a common drive shaft 198. The shaft 198 in turn is driven by areversible motor 200, operating through a chain 202, attached to a gearsprocket in a conventional manner. Obviously, gear drives may beemployed instead of the chain and sprocket drives. When the motor 200 isenergized from the receiver 162, the four nut assemblies are rotatedeither clockwise or counterclockwise depending upon the voltage signalfrom the proximity sensor 160 which in turn depends on the difference inthe distance of the metal surface 34 of'the rotor 18 (FIG. 6) in thelower position to the upper position 160a of the sensor.

The means for moving the table 168 to the right or left as viewed inFIGS. 4 and 5 comprises a pair of hydraulic cylinders 204 and 206 havingmovable piston rods 208 and 210, respectively, projecting therefrom. Oneof the rods 208 or 210 isdriven against a push block 212 or 214 mountedon the upper surface of the platform 172, so that when hydraulic fluidpressure in either cylinder 204 or 206 exceeds that of the othercylinder, theplatform 172is pushed in that direction. Accordinglylateral movement in a horizontal plane is accomplished.

As shown more particularly in FIG. 4, the platform 172 is provided witha keystone shaped aperture 216 with T-shaped lever arm 218 disposed overthe aperture and pivotally mounted on a pin 220 which is securedin theplate 170. The hydraulic cylinders are mounted on the lever arm 218. Thelever arm 218 includes a transverse portion 222 extending from oppositesides of the axis thereof and the opposite end of each portion isbifurcated to provide a pair of similar spaced prongs 224 and 226. Eachpair of the prongs is disposed between similar pairs of guide pins 228and 230, respectively, secured in the platform 172. As shown in FIG. 4,the push block 212 is disposed with a spaced clearance between thespaced prongs 224 so that upon actuation of the cylinder 204 the rod 208pushes against the block 212 to slide the paltform 172 to the left asviewed in FIG. 4. Similarly, the push block 214 is disposed between theprongs 226 so that the platform may be moved in the opposite directionupon actuation of the piston rod 210. To facilitate precise right orleft transverse movement of the platform the pins 228 and 230 bearagainst the surfaces of the corresponding prongs 224 and 226. Thepistons 204 and 206 are actuated in response to an energizing signalfrom the receiver 162 generated by a voltage signal from the proximityswitch when it senses a difference in the horizontal spacing between thesensor and the stator wall 32 in positions 160b as shwon in FIG. 6.

The means for skew or angular adjustment of the lift table includes anadjustment block 232 secured to the end of the lever 218 remote from thepivot pin 220 and a pair of similar hydraulic cylinders 234 and 236having pistons rods 238 and 240, respectively, attached to platform 172.The cylinders 234 and 236 extend upwardly through the aperture 216 sothat the piston rods 238 and 240 contact opposite sides of the block232. Accordingly, appropriate upon an energizing signal from thereceiver 162, as a result of an appropriate sensor voltage pulse one ofthe cylinders 234 and 236 receives more hydraulic pressure than theother and its piston rod moves the block 232 to the right or left asviewed in FIG. 4, thereby rotating the platform 172 about the pivot pin220 whereby to provide better alignment of the stator axis 158 with theaxis of the shaft 50. For that purpose only slight adjustments areusually necessary, such as up to about 4 of either side of the axis ofthe lever 218 thereby moving the opposite ends of the table 168 to thebroken line positions 242 or 244 on the left or right of the table asviewed in FIG. 4.

In operation the apparatus 10 provides means for automaticallypositioning a stator in a precise alignment as desired with the axis ofthe shaft 50 so that a grinding wheel may be energized for removing alayer of cured resinous material from the inner surface of the stator onwhich excessive amounts of resin are present. Only a minute or less isrequired to align a stator with excellent precision. The apparatus ofthe present invention constitutes a highly satisfactory means foreliminating the time consuming manual methods of aligning a stator andmechanically processing its bore. Fast and economical, as wellas'precise removal of the insulation during the repair of a motor orgenerator is accomplished as compared to what was previously known inthe prior art.

The hydraulic cylinders 204, 206, 234,and 236 are supplied fluid underpressure from a suitable source, for example, from a central hydraulictank holding fluid under a high pressure to which each cylinder isconnected by a conduit with an electrically controlled solenoid or motordriven valve which opens or closes upon the appropriate energizationfrom the receiver 162 so as to convey the fluid to the appropriatecylinder. Alternatively, each pair of pistons is connected to ahydraulic pump operatedby a reversible electric motor which operatesupon receipt of an energizing signal from receiver 162 to pump fluidunder pressure to the cylinders 204 and 206 are caused to operate tomove appropriate cylinder. When the table 168 has been moved to aposition where the sensor 160 does not generate a voltage, the receivercloses the valves or stops the motor operation.

It will be appreciated that electric motors driving a screw and nutarrangement can be substituted for the hydraulic pistons 204, 206, 234and 236 with equally good results.

' The receiver 162 comprises suitable amplifiers and control equipmentwell known in the synchroand servomechanism art. Briefly, the receiver162 receives a position signal corresponding to the angular position oflinkage 92 and sensor 160 with respect to the stator.

The voltage output of sensor 160 is then compared with the angularposition of the sensor to the bore of the stator, and either or bothmotors 200and hydraulic table 168 to move up or down or sideways. Thereceiver also receives a signal from the back and forth movement offrame 14 and compares this with the voltage output of the sensor as itdeviates its separation or spacing from the stator wall and any voltagegenerated by the sensor is appropriately amplified and produces anenergization signal to hydraulic cylinders 234 and 236 to skew table 168so that the stator bore is parallel to the shaft 50. Receivers toaccomplish these functions are well known and available. Thus atwo-stage DC servo amplifier such as is disclosed on pages 2-29 to 2-32in Basic Synchros and Servomechanisms by Van Volkenburgh, Noogle andNeville, Inc. published in I955 by John F. Rider Publisher, Inc. may beemployed, the voltage pulse from the sensor constituting the errorsignal supplied to transformer T-l. Three of these circuits, one foreach motor, are used.

In operating the apparatus so as to enable the voltage signals from thesensor 160 to the receiver 162 and then to the several adjusting motors200 and 234 and 236 on lift table 16 to cause the platform 172 to movewhereby the axis of stator 18 is aligned coaxially with the shaft 50,various techniques and a variety of electronic equipment may be used. Asone example, the voltage outputs from sensor 160 as it rotates withinthe core of the stator 18 can be separated'into three components. Two ofthe voltage components which can be employed to raise or lower the tableand move the table sideways, are the following: one'compares the voltageoutput at the top (or 0 position) and bottom (or 180 position) of thesensor with respect to the stator, and the other compares the voltageoutput at the front and back (or and 270) positions of the sensor withrespect to the stator. This separation of the voltage outputs of thesensor can be readily accomplished, for instance by providing a circularslip ring having four metal contact segments on the 0, 90, 180 and 270points on the ring which correspond to the same points or position onthe stator, with electrical insulation between the metal contactsegments. The slip ring is contacted by a rotating arm having a contactbrush connected by a lead to sensor moving in synchronism with therotation of shaft 50, for example, by a selsyn driver on shaft 50 and aselsyn motor driving the contact arm, so that the contact brush passesvoltage from the sensor to the 0 contact segment when the sensor is atthe top of the stator bore, and so on. The 0 and contact segments on theslip ring are connected to a suitable digital voltmeter or equivalentdevice so that the differences in the sensor voltage between the voltageat the and at't-he L80 contact segments is established. The digitalvoltmeter outputis then fed to a selsyn motor (or the equivalent) tocause it to operate to raise or lower the table, depending on the signof the move the table sideways to a sufficient extent that thevoltagewould be changed by half the digital voltmeter reading at the front andback of the stator.

With each revolution of the sensor, the digital voltmeters and themotors they control will make successively finer adjustments, if any areneeded, so that after a few revolutions at most the axis of the statoris within a very close coaxial alignment with shaft 50.

To adjust for angular misalignment of the stator with shaft 50, theframe 14 is moved to and from the stator, preferably with the shaft 50held stationary with the sensor located at the front or back of theinside surface of the stator core on a horizontal plane through thestator axis. The to and fro motion of the sensor generates a thirdvoltage component which varies if there is any difference in thedistance of the metal stator core wall in this horizontal traverse ofthe sensor 160. To secure this third voltage component, the sensoroutput is switched so that it does not go through the slip ringcontacts, but is fed to a third digital voltmeter at which the maximumvoltage difference is sensed and the digital voltmeter output is causedto actuate the angular adjustment mechanism cylinders and pistons 234,236, 238 and 240 to turn the platform 172 so that the stator axis isturned byan amount sufficient so that the next sensor traverse willindicate little, if any, angular misalignment. Progressively,corrections up to the limit of accuracy of the sensor may be effected byseveral successive traverses of the sensor 160.

Furthermore, the motor 200, and hydraulic cylinders 204, 206,234 and 236can be manually energized. To accomplish this the voltage output ofsensor 160 is observed on a voltmeter, and the operator can actuate theappropriate switch to move platform 172 up or down, sideways or to skewit until the voltage reading from the sensor is zero.

Since the stator bore is ordinarily reasonably precisely lined with itsaxis parallel to the bottom of its feet or support or mounting brackets,no provision need be made for angular adjustments of the stator in avertical plane about a horizontal axis. However, this can be readilyprovided for by placing a tiltable second table on top of table 168, andpivoting or brinding the front edge of the second table to table 168,and providing a hydraulic cylinder or a screw thread and nut assembly atthe rear end of the second table-and raising or lowering the secondtable therewith to provide for angular corrections along the horizontalaxis at the front hinge much as the angular adjustment is made on avertical axis via lever 218, pivot 220 and cylinders 204 and 206.

1 The sensor 160 can sense the necessary misalignment and enablethereceiver to operate the motor.

What is claimed is:

1. Apparatus suitable for removing a resinous coating from a cylindricalmetal surface of a motor stator, com- 12 prising a base, an uprightframe on the base, a support table on the base for mounting a motorstator and spaced from the frame, a shaft rotatably mounted on the framewith axis directed toward the support table, means for rotating theshaft, means for moving one of the frame and table toward and away fromeach other, an arm mounted on the end of the shaft nearer the table andextending substantially laterally of the shaft, means for mounting aspindle on the arm member and being movable along the arm to a selectedposition radially from the axis of the shaft, whereby the spindle ismovable in a circular path of travel along a radius from the shaft axis,means for rotating the spindle, means for moving the table vertically,laterally, in a horizontal plane and angularly-about a vertical axiswith respect to the base to align the axis ofa motor stator into coaxialalignment with the shaft, abrasion means mounted on the spindle capableof removing excess resin from the cylindrical metal surface of thestator, sensing means on the spindle for measuring any misalignment ofthe axis of the cylindrical. metal surface with the shaft as the sensingmeans is revolved within the stator, and means cooperatively associatedwith the sensing means and the means for moving the table whereby thestator axis is in concentric alignment with the shaft, the stator isaligned so that the abrasion means can remove substantially all theresin from the cylindrical metal surface.

2. The apparatus of claim 1 wherein the means for mounting the spindleincludes a mounting arm and movable lever means to which is attached thespindle means for controlled fine movement of the spindle means wherebythe grinding means 'on the spindle can be adjustably movable radiallyinto and out of contact with the resinous coating on the stator surface.

3. The apparatus of claim 2 wherein the means for mounting the spindlemeans includes a lever-actuating means between the mounting arm and thelever means for positioning the grinding means against the resinouscoating.

4 The apparatus of claim 3 wherein the leveractuating means includes afluid operated bellows.

5. The apparatus of. claim 1 wherein the sensing means and the grindingmeans are detachably and interchangeably mounted on the spindle.

6. The apparatus of claim 1 wherein the means for moving the tablevertically, laterally, and angularly about a vertical axis compriseelectrically operated mechanisms controlled by electrical signalsderived from the sensing means.

7. An apparatus for automatically aligning the axis of a cylindricalworkpiece with the axis of a shaft of said apparatus and for thereafterperforming work on said cylindrical workpiece which work is parallel toand at a fixed distance from the axis of said cylindrical workpiececomprising:

1. a flat base;

2. a frame mounted on saidbase;

3. means for afixing said cylindrical workpiece to said base with itsaxis parallel thereto;

4. means for altering the distance between said frame and saidcylindrical workpiece along a first line parallel to said base;

5. first non-manual means for moving one of said frame and saidcylindrical workpiece along a second line perpendicular to said base;

6. second non-manual means for moving one of said frame and saidcylindrical workpiece along a line perpendicular to said first line andparallel to said base;

7. third non-manual means for rotating one of said frame and saidcylindrical workpiece about a line perpendicular to said base;

8. a shaft mounted on said frame parallel to said base and rotatablerelative to said frame;

9. means for rotating said shaft;

10. an arm mounted on said shaft and extending substantially laterallytherefrom;

l 1. means for mounting a tool on said arm for performing work on saidcylindrical workpiece;

l2. sensor means mounted on said arm, the output of 15 which is anelectrical signal proportional to the distance between said sensor meansand said cylindrical workpiece;

13. means for determining the position of said sensor means relative tothe ends of said cylindrical workpiece, to a third line perpendicular tothe axis of said cylindrical workpiece, and to a fourth lineperpendicular to said third line and perpendicular to the axis of saidcylindrical workpiece;

l4. electrical means for comparing the output of said sensor means atthree pairs of positions, the first pair being the positions of saidsensor means when it crosses said third line and 180 thereof, the secondpair being the positions of said sensor means when it crosses saidfourth line and 180 thereof, and the third pair being the positions ofsaid sensor means when it is near each end of said cylindricalworkpiece,

and, if the outputs of said sensor means'at any of the two positions ofone of said pairs of positions are unequal, for causing at least one ofsaid nonmanual means to move at least one of said frame and saidcylindrical workpiece so that said outputs are more equal.

8. An apparatus according to claim 7 wherein said second and third linesare parallel.

9. An apparatus according to claim 8 wherein said electrical meanscomprises three electrical circuits, a circuit for comparing the outputsof said sensor means at the two positions of said first pair ofpositions and for activating said first non-manual means if said outputsare unequal, a circuit for comparing the outputs of said sensor means atthe two positions of said second pair of positions and for activatingsaid second non-manual means if said outputs are unequal, and a circuitfor comparing the outputs of said sensor meansat the two positions ofsaid third pair of positions-and for actuating said third non-manualmeans if said outputs are unequal.

10. An apparatus according to claim 9 wherein said three electricalcircuits are three two-stage DC servoamplifiers.

11. An apparatus according to claim 7 wherein said base is horizontal.

12. An apparatus according to claim 7 wherein all of said non-manualmeans move said cylindrical workpiece.

13. An apparatus according to claim 7 wherein said sensor means is amagnetic proximity switch.

14. An apparatus according to claim 7 including means for moving saidsensor means along a line parallel to said shaft.

15. An apparatus according to claim 7 wherein said means for determiningthe position of said sensor means includes a slip ring having contactsat the 0, and 270 positions which are contacted by a contact brushmoving in synchronism with said shaft.

16. An apparatus according to claim 7 including a tool mounted bysaidmeans for mounting a tool.

17. An apparatus according to claim 16 wherein said tool is a grinder.

1. Apparatus suitable for removing a resinous coating from a cylindricalmetal surface of a motor stator, comprising a base, an upright frame onthe base, a support table on the base for mounting a motor stator andspaced from the frame, a shaft rotatably mounted on the frame with axisdirected toward the support table, means for rotating the shaft, meansfor moving one of the frame and table toward and away from each other,an arm mounted on the end of the shaft nearer the table and extendingsubstantially laterally of the shaft, means for mounting a spindle onthe arm member and being movable along the arm to a selected positionradially from the axis of the shaft, whereby the spindle is movable in acircular path of travel along a radius from the shaft axis, means forrotating the spindle, means for moving the table vertically, laterally,in a horizontal plane and angularly about a vertical axis with respectto the base to align the axis of a motor stator into coaxial alignmentwith the shaft, abrasion means mounted on the spindle capable ofremoving excess resin from the cylindrical metal surface of the stator,sensing means on the spindle for measuring any misalignment of the axisof the cylindrical metal surface with the shaft as the sensing means isrevolved within the stator, and means cooperatively associated with thesensing means and the means for moving the table whereby the stator axisis in concentric alignment with the shaft, the stator is aligned so thatthe abrasion means can remove substantially all the resin from thecylindrical metal surface.
 2. The apparatus of claim 1 wherein the meansfor mounting the spindle includes a mounting arm and movable lever meansto which is attached the spindle means for controlled fine movement ofthe spindle means whereby the grinding means on the spindle can beadjustably movable radially into and out of contact with the resinouscoating on the stator surface.
 2. a frame mounted on said base;
 3. meansfor afixing said cylindrical workpiece to said base with its axisparallel thereto;
 3. The apparatus of claim 2 wherein the means formounting the spindle means includes a lever-actuating means between themounting arm and the lever means for positioning the grinding meansagainst the resinous coating.
 4. The apparatus of claim 3 wherein thelever-actuating means includes a fluid operated bellows.
 4. means foraltering the distance between said frame and said cylindrical workpiecealong a first line parallel to said base;
 5. first non-manual means formoving one of said frame and said cylindrical workpiece along a secondline perpendicular to said base;
 5. The apparatus of claim 1 wherein thesensing means and the grinding means are detachably and interchangeablymounted on the spindle.
 6. The apparatus of claim 1 wherein the meansfor moving the table vertically, laterally, and angularly about avertical axis comprise electrically operated mechanisms controlled byelectrical signals derived from the sensing means.
 6. second non-manualmeans for moving one of said frame and said cylindrical workpiece alonga line perpendicular to said first line anD parallel to said base; 7.third non-manual means for rotating one of said frame and saidcylindrical workpiece about a line perpendicular to said base;
 7. Anapparatus for automatically aligning the axis of a cylindrical workpiecewith the axis of a shaft of said apparatus and for thereafter performingwork on said cylindrical workpiece which work is parallel to and at afixed distance from the axis of said cylindrical workpiece comprising:8. a shaft mounted on said frame parallel to said base and rotatablerelative to said frame;
 8. An apparatus according to claim 7 whereinsaid second and third lines are parallel.
 9. means for rotating saidshaft;
 9. An apparatus according to claim 8 wherein said electricalmeans comprises three electrical circuits, a circuit for comparing theoutputs of said sensor means at the two positions of said first pair ofpositions and for activating said first non-manual means if said outputsare unequal, a circuit for comparing the outputs of said sensor means atthe two positions of said second pair of positions and for activatingsaid second non-manual means if said outputs are unequal, and a circuitfor comparing the outputs of said sensor means at the two positions ofsaid third pair of positions and for actuating said third non-manualmeans if said outputs are unequal.
 10. an arm mounted on said shaft andextending substantially laterally therefrom;
 10. An apparatus accordingto claim 9 wherein said three electrical circuits are three two-stage DCservo-amplifiers.
 11. An apparatus according to claim 7 wherein saidbase is horizontal.
 11. means for mounting a tool on said arm forperforming work on said cylindrical workpiece;
 12. An apparatusaccording to claim 7 wherein all of said non-manual means move saidcylindrical workpiece.
 12. sensor means mounted on said arm, the outputof which is an electrical signal proportional to the distance betweensaid sensor means and said cylindrical workpiece;
 13. An apparatusaccording to claim 7 wherein said sensor means is a magnetic proximityswitch.
 13. means for determining the position of said sensor meansrelative to the ends of said cylindrical workpiece, to a third lineperpendicular to the axis of said cylindrical workpiece, and to a fourthline perpendicular to said third line and perpendicular to the axis ofsaid cylindrical workpiece;
 14. electrical means for comparing theoutput of said sensor means at three pairs of positions, the first pairbeing the positions of said sensor means when it crosses said third lineand 180* thereof, the second pair being the positions of said sensormeans when it crosses said fourth line and 180* thereof, and the thirdpair being the positions of said sensor means when it is near each endof said cylindrical workpiece, and, if the outputs of said sensor meansat any of the two positions of one of said pairs of positions areunequal, for causing at least one of said non-manual means to move atleast one of said frame and said cylindrical workpiece so that saidoutputs are more equal.
 14. An apparatus according to claim 7 includingmeans for moving said sensor means along a line parallel to said shaft.15. An apparatus according to claim 7 wherein said means for determiningthe position of said sensor means includes a slip ring having contactsat the 0*, 90*, 180* and 270* positions which are contacted by a contactbrush moving in synchronism with said shaft.
 16. An apparatus accordingto claim 7 including a tool mounted by said means for mounting a tool.17. An apparatus according to claim 16 wherein said tool is a grinder.